Hydraulic valve lifter



P 1954 L. J. VAN SLOOTEN 2,689,555

HYDRAULIC VALVE LIFTER Filed Aug. 7' 52 W Z 6/ i E 6 6/ I a g .1 J z I fly I V I] ;IL I are? #2 I ily I;

Y 37 3; y 241 w entor @219 JflaWfM/Y B I Atto y S Patented Sept. 21, 1954 HYDRAULIC VALVE LIFTER Louis J. Van Slooten, Holland, Mich., assignor to General Motors Corporation, Detroit, Mich., a

corporation of Delaware Application August 7, 1952, Serial No. 303,117

6 Claims. (01. 123-40) V 1 This invention relates to hydraulic valve lifters for automatically taking up excess lash in the valve trains of internal combustion engines and the like, and particularly to such lifters of the "self-contained type in which the hydraulic fluid is sealed within the assembly with no provision stem and its other end seated against the cylinfor its replenishment from any external source during operation.

The principal object of the invention is to provide an improved construction for lifters of the aforementioned type having the lifter plunger sealed to its operating cylinder by an expansible bellows located externally of both the cylin-, der and piston and in embracing relation with the lower end of the push rod or valve stem driven by the piston, the bellows being connected to the cylinder and a seat member for the push rod by novel means having advantages which both reduce the cost of construction and initial assembly, and enable the bellows unit to be formed as a subassemblyunit removable as such from the remainder of the lifter for service replacement.

Further objects and advantages of my invention will be readily apparent from the following description of a preferred embodiment thereof,

having reference to the drawing wherein:

Figure 1 is a sectional view of a'portion of an 2 having the usual piston 3. Closing the upper end of the cylinder 2 and forming a combustion chamber 4 above the piston is a cylinder head 6.

At 1 is a poppet valve controlling communication between a cylinder head port 8 and the combustion chamber 4 and having a stem 9slidably mounted for reciprocation in the cylinder head. In conventional manner, reciprocal movements of the valve 1, are effected by rotation of a cam II which is suitably supported in the crankcase I and driven in timed relation with movements of the piston 3. Completing the valve operating train, I have shown my lifter. I2 operatively engaging the cam I I and slidably supported for reciprocation in a lifter bore I3 formed inthe crankcase I.. Upward movements of the lifter are transmitted by the usual push rod I4 to an adjusting screw I6 fixed in one end of the rocker ll, which latter is arranged to oscillate about an axis represented by the rocker shaft I8 suitably supported on the cylinder headt, the other end of the rocker being in driving engagement with the upper end of the valve stem 9. A valve return spring I9 having one end secured to the valve der head is also shown, and serves to maintain the valve in closed position as illustrated in Figure 1.

As shown in Figure 2 the lifter I2 comprises telescoping cup shaped cylinder and piston members 2| and 22 arranged in nesting relation. Between the closed end of the lifter cylinder 2| and the adjacent end of the lifter piston 22 is a fluid pressure chamber 23 which isnormally maintained filled with fluid for transmitting thrust from the cylinder to the piston during opening movements of the engine valve 1. This pressure chamber 23 includes a lower well portion 24 which opens upwardly into an enlarged diameter portion 26 of preferably greater diameter than the bore 21 of the cylinder and extending upwardly beyond the lower endof the piston outer periphery. The lower end of the piston has an extension 28 of reduced diameter forming a shoulder 29 at its juncture with the main body of the piston. Loosely journaled on the extension 28 and having an external flange 3I rotatively seated against the shoulder 29 is a cup shaped cage member 32 whose end wall is provided with one or more apertures 33 which provide communication between the interior of the cage member and the portion of the chamber 23 externally thereof. Seated in the bottom of the well 24 and loosely centered by the side walls thereof is a lifter piston biasing spring 34 whose upper end loosely embraces the cage member 32 and maintainsits flange 3| seated against the shoulder 29 of the lifter piston. Extending through the bottom wall of the lifter piston and its extension 28 is a fluid supply passage 36,

through which fluid may pass from the interior of the piston to the pressure chamber 23. A check valve accommodating such fluid flow but preventing flow of fluid in the reverse or upward direction through the passage 36 is also provided in the form of a ball 31 which is of larger diameter than the passage 36. The seat for this ball3'I is formed by the lower end of the extension 28 immediately surrounding the passage 36, and when the ball is in engagement with this seat and the cage flange 3| is in abutment with the pistonshoulder 29 only a predetermined small clearance (on the order of .004r-a008) exists between the ball and the bottom wall of the cage member. The internal surface of the piston side walls are preferably formed as a series of decreasing diameter portions 38, 39, and 49, as shown, which arrangement lends strength to the lifter piston lower side and end walls while yielding the largest internal volume for purposes of fluid storage.

The cylinder side walls terminate at their upper end with an annular section 42 of reduced external diameter and increased internal diameter. Pressed into this annular portion 42 is a collar member 43 having a flange 44 intermediate its 3 ends which abuts against the upper end face of the cylinder portion 42 'and has its external periphery flush with the outer annular surface .of the portion 42. The internal diameter of the collar member 43 is substantially less than that of the cylinder bore 21 so as to overhang the latter as shown. Between its upper end and the flange 44 the external periphery of the collar member is relieved by an annular groove 46 to form a narrow flange 41 which defines the upper outer end collar member, and crimped around this flange 47 is the lower end of an expansible bellows 48. A fluid tight joint is secured between 'the bellows '48 and collar member 43 as bysold'ering or welding the two parts together as at '49 within the groove 46.

Forming a seat for the lower end of the push rod 14 is a member 5] having a flange 52 which rests on the upper edge of the piston side walls and a lower end'portion 53 having a slip fitjin the piston bore 38. flange 52 is made somewhat less than the bore "diameter of the lifter cylinder to provide an an- The external diameter of the nular space 54 therebetween. To provide continuous communication between this space 54 and the interior of the lifter piston below the push rod seat'member 51 a radial slot 56 is provided extending from the lower face of the end portion '53 to the lower outer 'periphery'of the flange 52. Above the flange 52 the seat member is of reduced'tran'sver'se section to'provide 'an annular space 51 between it and the collar member '43, and the upper end of the seat member is formed with an enlarged headportion 58 whose upper face is recessed as "at 59 to sock'etably receive the lower end of the push'rod l4.

'Press'fitted onto the-external periphery of the head portion58 is the lower counterbored end of a sleeve member 6l whose internal diameter above the head portion 58 looselyembraces the push rod I4. A shoulder 62 formed at the juncture of theinternal diameter "and the lower 'end counterbore of this sleeve member 6| abuts the upper'endface surrounding the recess '59 in the valve seat head 58. The upper end ofthe sleeve membe'rfil hasan external flange 63 whose outer j'p'eripher'y is 'circumferentially grooved "as at 6'4,

and the upper end of the bellows'me'mber "48 is sealed to this'flange by crimping the bellows material around the'lower'sidewall 56 of :the groove 64 and Welding or fsoldering as at '61. The internal diameter of thesleeve member'fil may be .enlarged'or flared at its upp'er'end assho'wn at 68 forthe purpose of directing the engine lubricating'oil =draining down the outside of the push rod'int'o the sleeve for lubricating the recess 59 'and the'abutting'lowerendof the push rod. The

bellows member 4 8 has its internal diameter larger than the outer periphery of the sleeve member Bl below the flange63 to prevent sliding 'frictionbetween these parts during lifter operation and to permit the bellows member being filled or "partially filled 'withhydraulic fluid at assembly.

In operation, lifting 'movements of the lifter cylinder "21 in response to'rotation of 'the'cam -l l are transmitted to the lifter piston '22 through the medium of the hydraulic fluid which is trapped within the pressure chamber 23 upon closure of the piston passage 36 resulting froin the ball check valve 31 moving to'its's'e'ated -position at the lower end of this passage in response to increased fiuid'pressur'e in the'cham'ber Z3. Continued upward movement of the lifter-cylinder is then accompaniedby upward movementof turn the lifter toiit's initial position after each lift stroke er the 6am. Any wear or thermal contraction of the parts which would tend to create an endwise clearance between the upper end of the engine valve stem and the cam when the engine "valve is in closed position is taken up by the lifter spring 34 urging the lifter piston out of its cylinder and the lifter cylinder against the operating face'of the cam. In order that the lifter may also accommodate any lengthening :of the valve 'trainiresulting from thermal expansion of the parts as the engine heats up "in operation, a certain amount of fluid leakage past the lifter piston from the pressure chamber 23 during each lift stroke is provided for in the -fltbetween the lifter piston 'and the cylinder bore 21 This-leak- "a'ge fluid is returned to the interior of the lifter piston via the'slot-56 in the push-rodseatEl. As

the volume of the pressure chamber is-restored by the action of the lifter spring --34 in urging the piston outwardly of its cylinder after each lifting stroke the resultant pressure drop in the chamber 23 permits the ball check valve to leave itsseat to-theextentprmitted by thecagemember '32 andsuiiicientfluid then flows downwardly through the passage 36 to replenish this *leakage from the chamber -23. At the start of the next lift stroke of the lifter-cylinder the fluidpressure inthe chamber 'againrisescausin'g the'b'all'check valve toagain seat-itself and the-operating'cycle to be repeated.

Abovethe flange 52, the annular space-51 between the push rodseat'member'and the'collar member 'as well as the annular space between the bellows member and-the sleeve member, provide additional storage-capacity for the hydraulic fluid. Leakage of this fluid to the exterior of the lifter-assembly =is'prevented'by the press fit of the collar member 43 in the cylinder and the press flt of the sleeve member on the head 58 of the push rod seat. In their normalpositions,

asshown'in-Figur'e 2, the flange "52 of the push rod seat isspaced belowthelower-end of the-collar member 43 sothatthere is ample communication between :the'annular space '51 and the-upper end of the slot 56.

The means described -f or securing the bellowsito the lifter cylinder'and push rod seat enables this aseatmember 5 l together with the sleeve member 6-3, bellows 4-8and collar member *44 'to be :pre-

assembled :as "a unit -f'orconvenient-initial installation andrepla'cem'ent in'service. Also, the'-collar member 43 being pressed'into'the upper end otthe-lifter cylinder 'andhaving an "internal diameter exceedingthat'of'the'push'rod seatffiange '52 takes the place": of the-conventional 'snap' ring or" other stop means for limiting outward movement of the 'pis'ton 'an'd push :rod seat when "the lifter assembly removed from "the engine.

Having thus 'describ'ed "a preferred structural embodiment illustrating the principles and advantages of my *invention, minor "modifications 'wi1l"reaclilysuggestthemselves to :persons-skilied the art. 'Su'ch modifications, however, shall not Z'depa'rt-ffrcim tlie 'spirit and scope of the in- "ton aiidicylinderimembers in slidably' nested relation and forming a fluid pressure chamber between their end walls, the interior of the piston forming a reservoir for fluid to be introduced to said chamber, an annular collar member having a. press fit in the cylinder member above the piston member, an annular seat member carried by the piston member and having a portion extending through and defining an annular space within said collar member in communication with said reservoir, a sleeve member having a press fit on the upperend of said seat member, and an expansible bellows surrounding said sleeve member, said bellows having its upper and lower ends sealed to the sleeve and collar members, respectively, and its lower end open to said annular space.

2. In a hydraulic lifter having a cylinder with oppositely closed and open ends and a piston reciprocably mounted in the cylinder, means above the piston forming a reservoir for fluid to be introduced to the closed end of the cylinder, said means including an annular collar having a press fit in the open end of the cylinder and a seat member having a portion abutting the piston and engageable with the underside of said collar member to limit movement of piston outwardly of the cylinder, a sleeve extending above said seat member having its lower end press fitted thereto, and an expansible bellows loosely surrounding said sleeve and forming a sealed connection between the upper end of said sleeve and said collar member.

3. In a hydraulic lifter having a cylinder with a bore open at one end and a piston slidably fitting said bore, said cylinder being provided at the open end of said bore with a pressed-on collar member having a diameter less than the cylinder bore diameter, a seat member carried by the piston having a portion extending within said collar member for engagement with a lifter driven member, said portion and collar member defining an annular space open to said bore end, and means forming a fluid tight connection between said collar and seat members consisting of a rigid sleeve and an expansible bellows in concentric relation, said sleeve and bellows having their upper ends sealed to each other and their lower ends sealed respectively to said collar and seat members.

4. In a fluid sealing and driven stem seating device adapted for assembly as a unit to a hydraulic lifter of the type having slidably interfitted cylinder and piston members with correspondingly presenting open ends, said device including an annular collarmember having a lower end portion adapted to be press fitted to the open end of the cylinder, a seat member having a portion extending concentrically of said collar member and terminating at its lower end with a portion adapted to rest on the piston, a sleeve forming an upward extension of said seat member,

said sleeve having its lower end press fitted onto said seat member, and an expansible bellows surrounding said sleeve having its upper end sealed to the upper end of said sleeve and its lower end sealed to said collar member, said first named seat member portion and said collar member defining an annular space for passage of fluid between the open end oi the cylinder and the interior of the bellows.

5. In a device for transmitting thrust to and. from a piston of a hydraulic lifter and forming a fluid tight joint between said piston and the lifter cylinder, an annular collar member having a cylindrical surface adapted to efiect a press fit with an opposing cylindrical surface of the lifter cylinder, a second member adapted to seat on the lifter piston and reciprocate therewith in the cylinder, said second member having a portion of reduced cross section extending outwardly of the cylinder in radially spaced relation with the internal periphery of said collar member and defining an annular space open at its lower end to the lifter cylinder, a sleeve having one end press fitted on the outwardly extended end of said second member, and an expansible bellows interiorly open to the upper end of said annular space and sealingly interconnecting the collar member and the opposite end of said sleeve.

6. In a hydraulic valve lifter having upwardly presenting cup shaped piston and cylinder members in sliding engagement with each other, an

annular seat member having a flange abutting the open end of the piston member and a portion depending from said flange having a slip fit with the internal periphery of the piston, said flange terminating radially in spaced relation to the bore of the cylinder to provide for passage of fluid therebetween, said seat member having a passage formed therein interconnecting the outer periphery of said flange and the interior of the piston below said seat member, said seat member having a reduced diameter portion extending above said flange and an enlargement at the upper end of said reduced portion, said enlargement being formed with an upwardly presenting recess forming a seat for the lower end of a valve actuating rod, a sleeve extending above said seat having a counterbore in its lower end press fitted to the outer periphery of said enlargement, the bore of said sleeve above said counterbore being of sufiicient diameter to accommodate free flow of oil draining down the external periphery of the valve rod to said seat, said sleeve being provided with an external flange adjacent its upper end, said sleeve flange having its external periphery relieved by a circumferential groove, said cylinder member terminating at its open end in an annular section of reduced external and increased internal diameters, an annular, collar member having a flange abutting the end face of said section and. a depending portion press fitted to the internal periphery of said section, said collar member having an internal diameter less than the diameterof said seat member flange and larger than the outside diameter of said sleeve, whereby said collar member constitutes a stop limiting movement of the piston and seat member outwardly of the piston while accommodating their movement inwardly of the cylinder with the sleeve, said collar member having a circumferential groove in its external periphery above the flange thereof, and an annular expansible bellows having its internal diameter spaced concentrically from the external periphery of the sleeve, said bellows having its upper end crimped into said groove in the seat member flange and its lower end crimped in said groove in the collar member.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,036,986 Halford Apr. 7, 1936 FOREIGN PATENTS Number Country Date 121,417 Australia May 16, 1946 

